Don,
On 11/22/2013 12:28 AM, Don Hill AA5AU wrote:
> So in other words, even though many of us are not against removing
> the symbol rate, for the sake of argument, we are to tell the FCC
> that we ARE in fact against removing the symbol rate in order to
> preserve the existing bandwidth regulation.
No, we don't need to tell the Commission that we are against removal
of the symbol rate limitation. We need to tell the Commission that
we are against the ARRL's Proposal to replace it with a *2.8 KHz*
bandwidth limitation.
1) Contrary to the ARRL's assertion that there is currently no
bandwidth limitation, 97.307 *also* includes a 1000 Hz *shift*
limitation. Reasonable persons would apply the shift limit to
the difference between the highest and lowest tone in multi-
tone modulations and conclude that the maximum permissible
bandwidth would be approximately 1500 Hz with a 300 bps symbol
rate (depending on the modulation index).
2) the history of US amateur data regulation - expressed in the
Commission's own statements when this issue was last addressed
in 1980 - says that the data rate limits were set to be consistent
with "traditional radioteleprinter bandwidths" which happen to be
approximately 300 Hz for 45.45 baud, 170 Hz shift RTTY as well as
300 Hz or less for PSK31, JT65A, JT9, WSPR and QRSS which together
comprise an overwhelming majority of all amateur HF "RTTY, Data"
activity - probably on the order of 80 to 90% or all such activity.
The approach it not to oppose ARRL's petition as a whole ... in my
opinion, the correct approach is to point out the problems with a
2.8 KHz limit in spectrum where 300 Hz or less is the norm, point out
that other than a single commercial implementation, current/recent
development work has been primarily with bandwidths of 300 Hz or less,
and suggest that the *appropriate* solution would be to substitute a
*500 Hz* bandwidth limit for the current 300 bps symbol rate and 1000
Hz shift limits.
One could further comment that if ARRL wished to propose 2.8 KHz wide
data modes, those would be appropriate in the spectrum currently used
for "voice, image". Not only would 2.8 KHz wide data be consistent
with other 2.8 KHz wide modulation modes in that spectrum, allowing
"RTTY, data" at up to 2.8 KHz bandwidth on those frequencies would
permit amateurs to experiment with other protocols such as M110A/B/C,
ALE, STANAG, etc. and additional flexibility in digital voice.
73,
... Joe, W4TV
On 11/22/2013 12:28 AM, Don Hill AA5AU wrote:
So in other words, even though many of us are not against removing
the symbol rate, for the sake of argument, we are to tell the FCC
that we ARE in fact against removing the symbol rate in order to
preserve the existing bandwidth regulation. This is still a bit
confusing to me but hopefully I'll figure it out. So far, my director
appears to be against the proposal. But I get the feeling the ARRL is
going to try to ramrod this thing through.
My post to the reflector regarding the RM assigned to this proposal
was sent to the moderator for approval (ARRL conspiracy?).
It's RM-11708 and so far I haven't found it up on the FCC site yet
although I'm not 100% I'm looking in the right place.
73, Don AA5AU
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